The present invention relates to a fire resistant polymeric film and insulation assembly, and, in particular, to an insulation assembly including a resilient insulation (such as but not limited to a glass fiber insulation) within a polymeric film envelope wherein the polymeric film envelope is fire resistant throughout or at least has an exposed surface layer that is fire resistant. The fire resistant insulation assembly of the present invention is especially suited for under floor and other applications where the insulation assembly is exposed on at least one side.
One form of encapsulated insulation assembly currently utilized to insulate residential, commercial and industrial buildings and other structures includes resilient fibrous insulation blankets that are made of glass or other insulation fibers. The fibrous insulation blankets are typically in roll or batt form and are enclosed within polymeric film envelopes to encapsulate any dust and/or loose insulation fibers within the insulation assemblies and avoid direct handling of the fibrous insulations which might cause irritation.
Most encapsulated insulation assemblies used in the insulation of residential, commercial and industrial buildings, such as polymeric film encapsulated glass fiber insulation assemblies, are enclosed within the walls or ceilings of the buildings and thus, are shielded from direct contact with the flames of a fire within the building at the initiation of a fire by the building panels, e.g. dry wall or other building panels enclosing the insulation assemblies within the wall or ceiling. However, in certain insulating applications the encapsulated insulation assemblies are exposed on at least one side, e.g. in under floor applications and in some garage or other applications where no dry wall or other building panels are used to form an interior wall. For these exposed applications, the encapsulated insulation assemblies may easily be directly exposed to flames at the initiation of a fire. Thus, there has been a need to provide self extinguishing polymeric film encapsulated insulation assemblies that will not facilitate the spread of a fire in either enclosed or exposed applications, but especially for exposed applications where the insulation assemblies are more likely to be exposed directly to the flames of a fire at the initiation of a fire.
High density polymeric films that are used to encapsulate fibrous insulation blankets normally have a low coefficient of friction and are quite slippery. The slippery nature of these polymeric films can create processing problems in the automatic encapsulating equipment utilized to encapsulate the fibrous insulation blankets within the polymeric film envelopes and result in reduced production efficiencies in the encapsulation portions of the manufacturing process. Thus, in addition to the need for self extinguishing polymeric films, there has been a need to provide such films with good handling characteristics (i.e. exterior surfaces with coefficients of friction sufficiently high to improve the processing of the polymeric films through the encapsulating equipment) without reducing the integrity required for such films in the encapsulating process or the later handling of the encapsulated insulation assemblies and while providing a good printing surface on the exterior surfaces of such polymeric films.
The fire resistant resilient insulation assembly of the present invention provides a solution to the above discussed problems by providing an encapsulated insulation assembly with a self extinguishing, essentially dripless, polymeric film envelope. The fire resistant polymeric film of the envelope has: the integrity required for the processing of the film during the encapsulating process and the later handling of the insulation assembly; and an exterior surface with a finish suited for printing and a relatively high coefficient of friction to facilitate the processing of the film during the encapsulating process and later handling of the insulation assembly. The term xe2x80x9cself extinguishingxe2x80x9d as used herein means that when the polymeric film is removed from contact with an open flame, the polymeric film will not support continued combustion. The term xe2x80x9cessentially driplessxe2x80x9d as used herein means that when an open flame is applied to the polymeric film, the polymeric film will burn and/or melt away at the flame front, but there is little or no dripping of the polymeric material as the polymeric film is being consumed by the flame.
The fire resistant insulation assembly of the present invention, includes: a resilient insulation and a fire resistant polymeric film or films forming a tubular envelope surrounding the resilient insulation. Preferably, the fire resistant polymeric film includes: 50 to 80 weight percent high density polymeric material; 5 to 45 weight percent linear low density polymeric material; 5 to 25 weight percent fire retardant comprising a halogen and a synergist in a polymeric carrier; 0 to 5 weight percent UV stabilizer; and 0 to 10 weight percent pigment, e.g. titanium dioxide.
Preferably, the polymeric encapsulating film forming the envelope or at least the exposed side of the envelope in the insulation assembly is a two layer coextruded film. The outer layer of the film is formed from a predominately linear low density polymer, e.g. a linear low density polyethylene, to provide the insulation assembly with a surface finish that is well suited for printing, e.g. logos, instructions, etc., and a coefficient of friction that facilitates the handling of the film though the encapsulating equipment. The predominately linear low density polymeric film layer also provides increased machine direction tear resistance. The inner layer of the two layer coextruded film is formed from a predominately high density polymer, e.g. a high density polyethylene, to provide the coextruded polymeric film the integrity (impact strength and tear resistance) required for processing and handling.